2. Not just old, but in use as such today. And not just numbers but "objects" too.

So there is:

0

NaN - not a number

and Null or None in Object Oriented Programming, which is programming that organizes itself around little (or big) chunks of data linked to sequences of computer operations. ("subroutines", "methods", functions, "procedures&quot . So if a method asks another method to produce an object from data and the data is inappropriate, then the other method fundamentally signals "no can do" by returning a zero, denoted Null or None, instead of a memory address where an actual object's data is stored..